A&P Chapter 6: Bone Tissue and the Skeletal System
Stimulates absorption of calcium and phosphate from digestive tract
calcitriol
Inhibits osteoclast activity and stimulates calcium uptake by bones
calcitonin
Runs down the center of each osteon and contains blood vessels, nerves, and lymphatic vessels
central canal
A fracture in which the skin remains intact
closed
When a bone is manipulated and set into its natural position without surgery
closed reduction
Growth in diameter can continue even after longitudinal growth ceases
appositional growth
The spongy bone and medullary cavity receive nourishment from _____ that pass through the compact bone
arteries
A thin layer of cartilage that reduces friction and acts as a shock absorber
articular cartilage
Where two bones come together
articulation
Three general classes of bone markings
articulations, projections, holes
A hard, dense connective tissue that forms most of the adult skeleton
bone
The _______ ___________ acts as a reservoir for a number of minerals important to the functioning of the body, especially calcium and potassium
bone matrix
The process in which matrix is resorbed on one surface of the bone and deposited on another is known as _______ ______
bone modeling
_______ facilitate movement by serving as points of attachments for muscles
bones
Most abundant mineral in bone and the most abundant mineral in the human body
calcium
Needed to make calcium phosphate and calcium carbonate, which form the hydroxyapatite crystals that give bone its hardness
calcium
The body deposits _____ in the bones when blood levels get too high and it releases ______ when blood levels drop too low (same word in both blanks)
calcium
_________ cannot be absorbed from the small intestine without vitamin D
calcium
______ ______ are essential for muscle contractions and controlling the flow of other ions involved in the transmission of nerve impulses
calcium ions
A semi-rigid form of connective tissue; provides flexibility and smooth surfaces for movement
cartilage
________ serves as a template to be completely replaced by new bone
cartilage
_________ does not become bone
cartilage
Several breaks result in many small pieces between two large segments
comminuted
Found under the periosteum and in the diaphyses of long bones, where it provides strength and protection
compact bone
The walls of the diaphysis are composed of hard, dense ______ _________
compact bone
________ ________ is dense so that it can withstand compressive forces, while ______ ______ has open spaces and supports shifts in weight distribution
compact bone, spongy bone
The tubular shaft that runs between the proximal and distal end of the bone
diaphysis
Flat bones consist of a layer of ______ (spongy bone) lined on either side by a layer of bone
dipole
Bone develops by replacing hyaline cartilage
endochondral ossiciation
Lines the medullary cavity and is where bone growth, repair and remodeling occur
endosteum
A layer of hyaline (transparent) cartilage in a growing bone AKA the growth plate
epiphyseal plate
On the ________ side of the epiphyseal plate, cartilage is formed. On the _____ side, cartilage is ossified
epiphyseal, diaphyseal
The wider section at each end of the bone and is filed with spongy bone
epiphysis
Intramembranous ossification begins during _______ _______
fetal development
-Typically thin and curved -Cranial bones, scapulae, sternum -Serves as point of attachment for muscles and often protect internal organs
flat bones
The last bones to ossify via intamembranous ossification are the _______ _______ ___ _____ ______
flat bones of the face
A broken bone
fracture
People who exercise regularly have _______ bone density then those who are more sedentary
greater
A partial fracture in which only one side of the bone is broken
greenstick
The most apparent functions of the skeletal system are the _____ ________- those visible by observation
gross functions
Increases length of long bones, enhances mineralization, and improves bone density
growth hormones
An opening or groove in the bone that allows blood vessels and nerves to enter the bone
holes
Controls the rate of growth
hormones
________ crystals give bones their hardness and strength while the _________ fibers give them flexibility so they aren't brittle
hydroxyapatite, collagen
-A condition characterized by abnormally high levels of calcium -Results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion and coma
hypercalcemia
-A condition characterized by abnormally low levels of calcium -Results in blood having difficulty coagulating, heart may skip beats or stop beating, muscles have a difficult time contracting, nerves may have difficulty functioning, bones may become brittle
hypocalcemia
One fragment is driven into the other, usually as a result of compression
impacted
The ______ and ______ structure of bone will change as stress increases or decreases so that bone is an ideal size and weight for the amount of activity it endures
internal, external
__________ ________ develops directly from sheets of mesenchymal (undifferentiated) connective tissue
intramembranous ossification
Complex shape -Vertebrae and facial bones -Protects internal organs
irregular bones
-Cylindrical in shape, longer that it is wide -Arms, legs, finger, toes -Function as levers; move when muscles contract
long bones
Five types of bones
long, short, flat, irregular, sesamiod
Structural component of bone (2)
magnesium, fluoride
As more ______ is produced, the chondrocytes in the center of the cartilaginous model grow in size
matrix
________ stress stimulates the deposition of mineral salts and collagen fibers
mechanical
Hollow region in the diaphysis that is filled with yellow marrow
medullary cavity
Break occurs at an angle that is not 90 degrees
oblique
Reduces inflammation that may interfere with osteoblast function
omega 3 fatty acids
A fracture in which at least one end of the broken bone tears through the skin; carries a high risk of infection
open
Requires surgery to expose the fracture and reset the bone
open reduction
Early osteoblasts appear in a cluster called an _____ ______
ossification center
-Responsible for forming new bone -Found in growing portions of the bone, including the periosteum and endosteum -Not mitotic -Synthesis and secrete the collagen matrix and calcium salts
osteoblasts
Four types of bone cells
osteoblasts, osteocytes, osteogenic cells, osteoclasts
-Responsible for bone resorption, or breakdown -Found on bone surfaces and at sites of old, injured, or unneeded bone -Multinucleated -Originate from monocytes and macrophages
osteoclasts
-The primary cell of mature bone and is the most common type of cone cell -Entrapped in a matrix -Not mitotic -Can communicate to each other through the canaliculi
osteocytes
Located inside spaces called lacunae
osteocytes
-Develop into osetoblasts -Undifferentiated and with high mitotic activity and they are the only bone cells that divide -Found in the deep layers of the periosteum and the marrow
osteogenic cells
The microscopic structural unit of compact bone
osteon
Stimulates osteoclast proliferation and resorption of bone by osteoclasts; promotes reabsorption of calcium by kidney tubules; indirectly increases calcium absorption by small intestine
parathyroid hormone
Membrane that covers cartilage
perichondrium
-_______ contains blood vessels, nerves, and lymphatic vessels that nourish compact bone -Tendons and ligaments attach here
periosteum
The _______ gland secrets growth hormones
pitutary
-Areas of the bone that projects above the bone -Attachment points for tendons and ligaments
projections
(Following the reserve zone) it is the next layer toward the diaphysis and contains stacks of slightly larger chondrocytes
proliferative zone
Red blood cells, white blood cells, and platelets are produced in _________ ____________
red marrow
Where hematopoiesis- the production of red blood cells- takes place
red marrow
______ __________ fills the spaces in the spongy bone
red marrow
Resorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone to replace that which is resorbed
remodeling
The region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix
reserve zone
-Small and round; embedded in tendons -Patella -Protects tendons from compressive forces
sesamoid bones
promote osteoblastic activity and production of bone matrix; responsible for adolescent growth spurt; promote conversion of epiphyseal plate to epiphyseal line
sex hormones
-Cube like in shape, being approximately equal in length, width, and thickness -Tarsals and carpals -Provide stability and support as well as some limited motion
short bones
The following are functions of what system? -supports the body -facilitates movement -protects internal organs -produces blood cells -stores and releases minerals and fats
skeletal
Bone segments are pulled apart as a result of a twisting motion
spiral
When blood levels of calcium get too high, the ______ gland is stimulated to release calcitonin
thyroid
A hormone secreted by the thyroid
thyroxine
Stimulates bone growth and promotes synthesis of bone matrix
thyroxine
In spongy bone, lacunae and osteocytes are found in a lattice-like network of matrix spikes called ________
trabeculae
Occurs straight across the long axis of the bone
transverse
Needed for calcium absorption
vitamin D
_________ is not found naturally in many foods
vitamin D
Support bone mineralization; may have synergistic effect with vitamin D
vitamin K
Two types of bone marrow
yellow and red
Contains adipose tissue; the triglycerides stored in the adipocytes of the tissue can serve as a source of energy
yellow marrow
Most of the chondrocytes in this zone are dead because the matrix around them has calcified (zone closest to the diaphysis)
zone of calcified matrix
Chondrocytes are older and larger than those in the proliferative zone
zone of mautration and hypertrophy